Process for Upgrading Heavy and Highly Waxy Crude Oil Without Supply of Hydrogen

ABSTRACT

A continuous process to upgrade heavy crude oil for producing more valuable crude feedstock having high API gravity, low asphaltene content, and high middle distillate yield, low sulfur content, low nitrogen content, and low metal content without external supply of hydrogen and/or catalyst. Heavy crude oil having substantial amount of asphaltene and heavy components is mixed with highly waxy crude oil having large amount of paraffinic components and water to decompose asphaltene compounds and remove sulfur, nitrogen, and metal containing substances under supercritical conditions. Product has higher API gravity, lower asphaltene content, high middle distillate yield, lower sulfur content, lower nitrogen content, and lower metal content to be suitable for conventional petroleum refining process.

RELATED APPLICATIONS

This patent application claims priority to U.S. Provisional PatentApplication Ser. Nos. 60/990,662; 60/990,648; 60/990,658; 60/990,670;and 60/990,641 filed on Nov. 28, 2007, and is a continuation of U.S.patent application Ser. No. 12/277,255, filed Nov. 24, 2008, which areall incorporated by reference in their entireties.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a continuous process for upgradingheavy crude oil and highly waxy crude oil to produce more valuable crudeoil feedstock having a higher API gravity; lower asphaltene content;lower content of sulfur, nitrogen and metallic impurities; increasedmiddle distillate yield; and/or reduced pour point.

BACKGROUND OF THE INVENTION

The petroleum industry has long sought to find new methods for treatingheavy crude oils, highly waxy crude oils, and other petroleum materialsin an effort to meet the ever-increasing demand for petroleum feedstocksand improve the quality of available crude oils used in refineryprocesses.

In general, heavy crude oils have a low API gravity, high asphaltenecontent, low middle distillate yield, high sulfur content, high nitrogencontent, and high metal content. These properties make it difficult torefine heavy crude oil by conventional refining processes to produce endpetroleum products with specifications that meet strict governmentregulations.

Many petroleum refineries perform conventional hydroprocessing afterdistilling crude oil into various fractions. Each fraction is thenhydroprocessed separately. Therefore, refineries must utilize complexunit operations to handle each fraction. Further, significant amounts ofhydrogen and expensive catalysts are utilized in conventionalhydrocracking and hydrotreating processes under severe reactionconditions to increase the yield from heavy crude oil towards morevaluable middle distillates and to remove impurities such as sulfur,nitrogen, and metals.

Additionally, distillation and/or hydroprocessing of heavy crude oilfeedstock produces large amounts of asphaltene and heavy hydrocarbons,which must be further cracked and hydrotreated to be utilized.Conventional hydrocracking and hydrotreating processes for asphaltenicand heavy fractions also require high capital investments andsubstantial processing.

Currently, large amounts of hydrogen are used to adjust the propertiesof fractions produced from conventional refining processes in order tomeet required low molecular weight specifications for the end products;to remove impurities such as sulfur, nitrogen, and metal; and toincrease the hydrogen-to-carbon ratio of the matrix. Hydrocracking andhydrotreating of asphaltenic and heavy fractions are examples ofprocesses requiring large amounts of hydrogen, and these two processesresult in the catalyst having a reduced life cycle.

Supercritical water has been utilized as a reaction medium for crackingof hydrocarbons with the addition of an external source of hydrogen.Water has a critical point at about 705° F. (374° C.) and about 22.1MPa. Above these conditions, the phase boundary between liquid and gasfor water disappears, with the resulting supercritical water exhibitinghigh solubility toward organic compounds and high miscibility withgases. Furthermore, supercritical water stabilizes radical species.

However, utilizing supercritical water, without the use of externalhydrogen as the reaction media for cracking, has some disadvantages suchas coke formation, which occurs during the upgrading of hydrocarbons inthe supercritical water fluid. Although the amount of coke produced fromupgrading hydrocarbon in this manner is less than that produced byconventional thermal coking processes, coking must be minimized toincrease liquid yield and improve the overall stability of processoperation.

It is known in the industry that coke formation occurs in cracking usingsupercritical water if there is only a limited availability of hydrogenand feed hydrocarbon has high aromaticity. Several proposals have beensuggested to supply external hydrogen to a feed hydrocarbon treated withsupercritical water fluid. For example, hydrogen gas can be addeddirectly to the feed stream. Carbon monoxide can also be added directlyto the feed stream to generate hydrogen through a water-gas-shift (WGS)reaction between carbon monoxide and water. Organic substances such asformic acid can also be added to the feed stream to generate hydrogenthrough a WGS reaction with carbon monoxide, which is produced fromdecomposition of added organic substances and water. Additionally, asmall amount of oxygen can be included in the feed stream to allow foroxidation within the feed matrix for generating carbon monoxide. Thiscarbon monoxide can then be used in a WGS reaction for producinghydrogen. However, feeding external as and/or organic substances into aliquid stream increases costs and introduces added complexity to theprocess.

Highly waxy crude oil contains substantial quantities of paraffiniccompounds that have elevated boiling points and considerable molecularweights. These properties result in high pour points and difficulties inthe transferring capability of the crude oil through pipelines and oiltankers. Thus, highly waxy crude oil has come to be regarded as anon-conventional petroleum source. Furthermore, the highly waxy crudeoil has a very low content of unsaturated hydrocarbons, which makes itunsuitable as a feedstock for most current refining processes andpetrochemical processes. For example, to distill straight-run naphthafrom highly waxy crude oil requires severe reforming treatment toincrease aromatic and olefinic contents for improving octane rating ofmotor gasoline.

Upgrading of highly waxy crude oil is possible through conventionalthermal or catalytic cracking, but such treatment produces substantialamounts of coke and consumes large amounts of hydrogen and catalyst. Inaddition to thermal and catalytic cracking, the problems caused by thehigh pour point of highly waxy crude oil can be reduced by solventdewaxing and/or addition of pour point depressants. However, all ofthese methods suffer disadvantages.

As noted earlier, thermal coking produces large amounts of solid coke asa by-product, which is an indicator of the loss of valuable hydrocarbonfeedstock. Catalytic hydrocracking requires large amounts of hydrogenand the regular replacement of spent catalyst. Solvent dewaxing requiresa wax disposing system and a solvent recovery system, which adds tocomplexity and expense. Pour point depressants are expensive and changethe end product in undesirable ways.

Therefore, it would be desirable to have an improved process forupgrading heavy and highly waxy crude oils with supercritical waterfluid that requires neither an external supply of hydrogen nor thepresence of an externally supplied catalyst. It would be advantageous tocreate a continuous process and apparatus that allows for the upgrade ofthe whole crude oil, rather than the individual fractions, to reach thedesired qualities such that the refining process and various supportingfacilities can be simplified. Furthermore, it would be desirable to havea process that could be implemented at the production site without theuse of complex equipment. Additionally, it would be most desirable tomake the process be one that is conducted in a continuous fashion.

SUMMARY OF THE INVENTION

The present invention is directed to a continuous process that satisfiesat least one of these needs. The invention includes a continuous processfor upgrading a heavy crude oil feed stream in the absence of externallysupplied hydrogen. In one embodiment of the present invention, a mixtureof heavy crude oil and highly waxy oil are contacted together in thepresence of water under conditions that exceed the supercritical pointof water. Furthermore, there is an absence of externally suppliedhydrogen during this mixing step. In contacting the heavy crude oil andhighly waxy crude oil under supercritical conditions, at least a portionof hydrocarbons within the mixture will undergo cracking. The mixture isthen cooled, depressurized, and separated into a gas portion and aliquid portion. The liquid portion is then further separated intorecovered water and upgraded oil, whereby the upgraded oil is anupgraded heavy crude oil having reduced amounts of asphaltene, sulfur,nitrogen and metal containing substances in comparison with the heavycrude oil.

In an alternate embodiment of the present invention, the continuousprocess includes combining a heavy crude oil feed with a water feed inthe presence of highly waxy crude oil to create a modified heavy crudeoil/water mixture. The modified heavy crude oil/water mixture, which ismaintained at a pressure exceeding the critical pressure of water, whichis about 22.1 MPa, undergoes temperature modifications in a reactionzone in order to force the water into a supercritical state, therebyproviding a reaction medium for the upgrading of heavy crude oil withoutsignificant formation of coke. The reaction zone comprises an interiorportion of a main reactor, the main reactor operable to withstandtemperatures and pressures in excess of the critical temperature andcritical pressure of water, and the reaction zone is essentially free ofan externally-provided catalyst and essentially free of anexternally-provided hydrogen source. The highly waxy crude oil suppliesenough hydrogen to break the large asphaltenic molecules contained inthe heavy crude oil. Additionally, desulfurization, denitrogenation anddemetallation processes are accelerated by the presence of the highlywaxy crude oil.

Once the modified heavy crude oil/water mixture reaches an appropriatetemperature and pressure, at least a portion of the hydrocarbons in themixture undergo cracking, resulting in a hot adapted-mixture. This hotadapted-mixture is subsequently cooled and relieved of its increasedpressure, creating a pressure-reduced adapted mixture. Thepressure-reduced adapted mixture is then separated into a gas portionand a liquid portion, where the liquid portion is made up of an upgradedoil/water mixture. The final upgraded oil product, which has a higherAPI gravity; reduced amounts of asphaltene, sulfur, nitrogen or metalcontaining substances; and increased amounts of middle distillate yieldas compared to the heavy crude oil, is collected by separating theupgraded oil/water mixture into its two components, upgraded oil andrecovered water, using any suitable oil-water separator.

In an alternate embodiment, the reaction zone comprises an interiorportion of a generally vertically oriented reactor, such that themodified heavy crude oil/water mixture flows downwardly through thegenerally vertically oriented reactor.

In an alternate embodiment of the present invention, the modified heavycrude oil/water mixture is fed into a heating zone prior to the reactionzone, wherein the modified heavy crude oil/water mixture is heated to atemperature in the range of about 150° C. to about 350° C. to form apre-heated mixture. The pre-heated mixture is then introduced into thereaction zone, wherein the temperature within the reaction zone isincreased to a target temperature that is at or above the criticaltemperature of water, such that at least some of the hydrocarbons of thepre-heated mixture undergo cracking, forming the hot adapted-mixture,the reactor being essentially free of an externally-provided catalystand free of an externally-provided hydrogen source. The hot adaptedmixture is cooled and depressurized forming the pressure-reduced adaptedmixture. The pressure-reduced adapted mixture is then separated into thegas portion and the liquid portion, wherein the liquid portion is madeup of the upgraded oil/water mixture. The final upgraded oil product,which has reduced amounts of asphaltene, sulfur, nitrogen or metalcontaining substances as compared to the heavy crude oil, is collectedby separating the upgraded oil/water mixture into its two components,upgraded oil and recovered water, using any suitable liquid separator.

In other embodiments of the invention, the recovered water from thefinal liquid separation stage can be recombined with the water feed. Inyet another embodiment of the invention, the recovered water can betreated in an oxidation reactor prior to recombining with the water feedusing an oxidation step, so as to treat the recovered water by removingany oil residue or other impurities. In a further embodiment of thisinvention, the thermal energy contained in the product stream from thereaction zone and/or the oxidation reactor can be captured and used forheat exchange elsewhere in the process. Furthermore, the continuousprocess can be carried out without the aid of any externally suppliedcatalysts.

Additionally, the present invention provides a continuous process forconverting highly waxy crude oil to more valuable hydrocarbon feedstockwith a reduced waxy fraction and reduced level of impurities such assulfur, nitrogen and metal without forming significant amount of cokeand without an external supply of hydrogen or hydrogen-generatingchemicals. The low-value, highly waxy crude oil is upgraded toconventional crude oil that has improved flowing properties for moreeffective transfer in pipeline and tankers.

In an alternate embodiment of the present invention, a method forproducing upgraded hydrocarbon feedstock by supercritical water isprovided. In this embodiment, the water feed is heated, preferably inthe heating zone, to form a heated water stream, such that the heatedwater stream is in a supercritical state. The heavy crude oil is mixedwith the highly waxy crude oil before or after combining the heavy crudeoil with the heated water stream to create the pre-heated mixture. Thepre-heated mixture then enters the reaction zone, which is maintained ata pressure exceeding the critical pressure of water, and is heated to atarget temperature in the range of 705° F. to 1112° F. (374° C. to 600°C.). At this increased temperature and pressure, at least a portion ofthe hydrocarbons in the mixture undergo cracking, resulting in the hotadapted-mixture. This hot adapted-mixture is subsequently cooled andrelieved of its increased pressure, creating the pressure-reducedadapted mixture. The pressure-reduced adapted mixture is then separatedinto the gas portion and the liquid portion, where the liquid portion ismade up of the upgraded oil/water mixture. The final upgraded oilproduct, which has reduced amounts of asphaltene, sulfur, nitrogen ormetal containing substances as compared to the heavy crude oil, iscollected by separating the upgraded oil/water mixture into its twocomponents, upgraded oil and recovered water, using any suitable liquidseparator. At the same time, highly waxy crude oil is also upgraded toproduce an upgraded oil product having a lower pour point and higherconcentration of olefin and aromatic compounds.

In an alternate embodiment, the reaction zone comprises an interiorportion of a main reactor, wherein the main reactor is comprised of agenerally vertically oriented reactor, such that the pre-heated mixtureflows downwardly through the generally vertically oriented reactor.

The upgraded oil preferably has a higher API gravity, lower asphaltenecontent, higher middle distillate yield, lower sulfur content, lowernitrogen content, and lower metal content than the original heavy crudeoil feed, which allows for convenient processing in conventionalpetroleum refining processes. Also, an embodiment of the presentinvention provides an efficient and convenient method to upgrade heavycrude oil and/or highly waxy crude oil without forming significantamount of coke.

In an embodiment of this invention, supercritical water fluid providesan improved reaction medium for crude oils to be decomposed and crackedinto low molecular weight hydrocarbons through facilitating massdiffusion, heat transfer, intra- or inter-molecular hydrogen migration,stabilizing of radical compounds for suppressing coke formation andincreasing liquid yield, and removal of impurities. Furthermore,supercritical water fluid facilitates mass transfer, which increasesreaction speed. In one embodiment, the residence time of the pre-heatedmixture within the reaction zone is between 0.1 and 10 minutes, and morepreferably between 1 and 3 minutes.

The present invention does not require an external supply of hydrogenand/or hydrogen generating chemicals because the paraffinic fraction ofhighly waxy crude oil serves as a hydrogen source. In addition, externalcatalysts are not required.

Additionally, the continuous process of the present invention can beeasily utilized at the production site of the heavy crude oil or thehighly waxy crude oil because the preferred embodiment does not requirecomplex equipment or facilities associated with other processes thatrequire hydrogen supply or coke removal systems. In one embodiment, thecontinuous process of the present invention is located at the highlywaxy crude oil production site so as to minimize initial transportationcosts.

In one embodiment of the present invention, a continuous process forupgrading a heavy crude oil in an environment free of an externallysupplied catalyst or externally supplied hydrogen source is provided.The continuous process includes contacting a mixture of heavy crude oiland highly waxy oil in the presence of water under conditions thatexceed the supercritical point of water. In doing this, at least aportion of hydrocarbons in the mixture of heavy crude oil and highlywaxy oil undergo cracking. Advantageously, this cracking can be achievedin the absence of externally supplied hydrogen. Once the hydrocarbonsare cracked, the mixture is then cooled and depressurized prior toseparating the mixture into a gas portion and a liquid portion. Theliquid portion is then further separated into recovered water andupgraded oil, whereby the upgraded oil is an upgraded heavy crude oilhaving reduced amounts of asphaltene, sulfur, nitrogen and metalcontaining substances in comparison with the heavy crude oil.

The present invention is also directed to an apparatus for upgradingheavy crude oil and highly waxy crude oil in an environment free of anexternally supplied catalyst or externally supplied hydrogen source. Inone embodiment of the present invention, the apparatus includes a mixingzone, a pre-heating zone, a high pressure pumping means, a reactionzone, a pressure regulating device, a liquid-gas separator, and awater-oil separator. In one embodiment, the mixing zone is operable tocombine heavy crude oil and highly waxy crude oil with a water feed at aslightly elevated temperature. Slightly elevated temperatures aretemperatures that are slightly elevated in comparison to ambienttemperature. Exemplary elevated temperatures include temperatures in therange of 50-150 degrees C. The pre-heating zone is fluidly connectedwith the mixing zone; with the pre-heating zone being operable to heatits contents to a temperature up to about 350° C. The high pressurepumping means is operable to increase pressure of the oil/water mixturewithin the apparatus to exceed the critical pressure of water. Thereaction zone comprises an interior portion of a main reactor. Thereaction zone is fluidly connected with the pre-heating zone, and themain reactor is operable to withstand a temperature that is at least ashigh as the critical temperature of water. Additionally, the mainreactor is operable to withstand pressure in excess of the criticalpressure of water. In one embodiment of the present invention, thereaction zone is essentially free of an externally-provided catalyst andessentially free of an externally-provided hydrogen source.

BRIEF DESCRIPTION OF THE DRAWING

So that the manner in which the above-recited features, aspects andadvantages of the invention, as well as others that will becomeapparent, are attained and can be understood in detail, more particulardescription of the invention briefly summarized above may be had byreference to the embodiments thereof that are illustrated in thedrawings that form a part of this specification. It is to be noted,however, that the appended drawings illustrate only preferredembodiments of the invention and are, therefore, not to be consideredlimiting of the invention's scope, for the invention may admit to otherequally effective embodiments.

FIG. 1 shows one embodiment of the present invention.

FIG. 2 shows an embodiment of the invention that includes a recyclestream.

FIG. 3 shows an alternate embodiment of the invention.

FIG. 4 shows an alternate embodiment of the invention.

FIG. 5 shows an alternate embodiment of the invention.

FIG. 6 shows an alternate embodiment of the invention.

FIG. 7 shows an alternate embodiment of the invention.

FIG. 8 shows an alternate embodiment of the invention.

FIG. 9 shows an alternate embodiment of the invention.

FIG. 10 shows an alternate embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

While the invention will be described in connection with a series ofembodiments, it will be understood that it is not intended to limit theinvention to only those embodiments. On the contrary, it is intended tocover all the alternatives, modifications and equivalence as can beincluded within the spirit and scope of the invention defined by theclaims.

An embodiment of the present invention provides a continuous process forupgrading a crude oil feedstock, made up of heavy crude oil and highlywaxy crude oil, that comprises contacting the feedstock with hot,pressurized, supercritical water to produce an improved feedstock havinga higher API gravity, fewer asphaltenic and heavy components, highermiddle distillate yield, and a reduced amount of sulfur, nitrogen andmetallic components. The supercritical water stabilizes radicalmolecules, which suppresses any recombination of radicals, therebyresulting in diminished coke formation. The improved feedstock is formedwithout the need for an external supply of hydrogen, hydrogen-generatingchemicals, or catalyst.

An embodiment of the present invention also provides a continuousprocess for upgrading highly waxy crude oil such that the upgraded crudeoil has a reduced pour point, reduced amount of asphaltenic components,and increased middle distillate yield. This result is achieved withoutforming a significant amount of coke and without the need for anexternal supply of hydrogen or hydrogen-generating chemicals, orcatalyst.

According to an embodiment of the present invention, heavy crude oil ismixed with highly waxy crude oil at a slightly elevated temperature toproduce a modified heavy crude oil, the slightly elevated temperatureexceeding the pour point of the highly waxy crude oil. The modifiedheavy crude oil is then preferably fed through a high pressure pump inorder to increase the pressure of the modified heavy crude oil to avalue exceeding the critical pressure of water. The pressurized modifiedheavy crude oil is then preferably slightly heated to an elevatedtemperature in the range from 50° F. to 392° F. (10° C. to 200° C.), andmore preferably 122° F. to 322° F. (50° C. to 150° C.).) However, if thetemperature of the pressurized modified heavy crude oil should exceed302° F. (150° C.) at this increased pressure, coking can occur withinthe continuous process, which greatly reduces the efficiency of theoverall production. Therefore, a maximum temperature of 302° F. (150°C.) is most preferable for the pressurized modified heavy crude oil.Heating for this purpose can be accomplished, for example, by flowingthe modified heavy crude oil and a product stream from a reactor througha heat exchanger.

Water can be added to the heavy crude oil before or after combining withhighly waxy crude oil; however, the highly waxy crude oil is preferablymixed with the heavy crude oil before the water. The weight ratio, asmeasured at room temperature, of the heavy crude oil and the highly waxycrude oil is preferably in the range of 50:1 to 1:1, more preferably inthe range of 20:1 to 2:1. The weight ratio, as measured at roomtemperature, of the modified heavy crude oil and water is in the rangeof 10:1 to 1:10, more preferably in the range of 5:1 to 1:5. Thecombination of the heavy crude oil, the highly waxy crude oil and waterresults in the modified heavy crude oil/water mixture.

In one embodiment, the modified heavy crude oil/water mixture, which ismaintained at a pressure exceeding the critical pressure of water, isthen introduced into a heating zone, which preferably consists of aheater and tube, to increase the temperature of the modified heavy crudeoil/water mixture up to 302° F. to 662° F. (150° C. to 350° C.), andforming the pre-heated mixture. The heating zone is important to thesuccess of the continuous process as it helps reduce overall cokeformation. Heating for this purpose can be achieved, for example, bycombining the modified heavy crude oil/water mixture with a productstream from a reactor into a heat exchanger. In an alternate embodiment,highly pressurized water can be separately heated to a temperatureexceeding its critical temperature prior to mixing with the pressurizedmodified heavy crude oil.

The pre-heated mixture is then fed into the reaction zone, which ispreferably surrounded by another heater, to increase the temperature ofthe feed stream up to a target temperature of about 705° F. to 1184° F.(374° C. to 640° C.) while maintaining pressure above the criticalpressure of water to form the hot adapted-mixture. The hot adaptedmixture is then cooled down and undergoes a pressure release by apressure regulating device, forming the pressure-reduced adaptedmixture. The pressure regulating device is preferably a back pressureregulator (BPR), and more preferably more than one BPR in parallel. Thepressure-reduced adapted mixture is then separated into gas and liquidportions by a series of suitable separators. The liquid portion is thenseparated into upgraded oil and the recovered water by an oil-waterseparator.

Optionally, the recovered water from the oil-water separator is treatedwith oxygen under supercritical conditions in the oxidation reactor toremove oily impurities contained in the water phase. Oxygen used forthis purpose can be supplied from oxygen gas, hydrogen peroxide, organicperoxide, and/or air. The product from the oxidation reactor has highthermal energy released from the oxidation reaction. In alternateembodiments, this energy can be captured and used to heat the pre-heatedmixture, the heavy crude oil, the highly waxy crude oil, the modifiedheavy crude oil, the modified heavy crude oil/water mixture and/or thewater feed via a heat exchanger.

The upgraded oil phase recovered from oil-water separator contains areduced amount of asphaltenic, heavy and waxy components, sulfur,nitrogen and metals than the heavy crude oil. The distillation curve, asmeasured according to ASTM D-86, is also shifted to lower temperature bythis invention.

The continuous process of the present invention can comprise one or moreof the following: a crude oil-water mixing stage, a heating stage, areaction zone stage, a cooling stage, a depressurizing stage, and atleast one separating stage. Thermal energy contained in the productstream from the reaction zone stage can be utilized to treat the feedstream in suitably-sized economizing equipment.

Additionally, organic compounds included in the recovered water can befully oxidized with hot and pressurized water in the presence of oxygento obtain clean water for recycling and thermal energy that is releasedfrom oxidation reactor.

This invention provides a method to convert heavy crude oil to morevaluable hydrocarbon feedstock having: a higher API gravity; higherdistillation yield toward middle distillates; lower content ofimpurities, such as sulfur, nitrogen and metal; and lower contents ofasphaltenic and heavy fractions. These properties are achieved allwithout forming a significant amount of coke and without external supplyof hydrogen or hydrogen-generating chemicals. Products made by thisinvention are suitable for conventional refining processes that havelimited capability for hydrocracking and hydrotreating of fractionsderived from heavy crude oil.

The continuous process of the present invention is further demonstratedby the following illustrative embodiment, which is not intended to limitin any way the continuous process of the present invention.

Illustrative Embodiment

Properties of heavy crude oil that are applicable to the methoddisclosed in the present invention are listed in Table 1. Residualfraction having boiling points above 1050° F. (565.6° C.) is 23.6 vol %of whole range heavy crude oil and has asphaltenes as much as 8.2 wt %.

TABLE 1 Property Value Gravity, °API 27.4 Sulfur, Total Weight % 2.90Reid Vapor Pressure, psi 6.5 Pour Point, (Upper), ° F. 0 Salt, Lbs.NaCl/1000 BBL (PTB) 2 Ash, wt ppm 268 Vanadium, wt ppm 59 MicrocarbonResidue, wt % 8.1 Nickel, wt ppm 19 Nitrogen, wt ppm 1670 Heating Value,Gross, BTU/Lb 18620 Kin Viscosity, @ 70° F., SUS 191.97 Kin Viscosity, @100° F., SUS 68.07 Debutanized Crude Gravity, °API 26.40Characterization Gravity, °API 27.80

Properties of waxy crude oil that are applicable to the method disclosedin the present invention are listed in Table 2. Pour point is very high,105° F. (40.6° C.), which means the highly waxy crude oil is solid-stateat room temperature (68° F. to 86° F. (20° C. to 30° C.)).

TABLE 2 Property Value Gravity, °API 34.3 Sulfur, Total Weight % 1.8Reid Vapor Pressure, psi 4.1 Pour Point, (Upper), ° F. 105 Salt, Lbs.NaCl/1000 BBL (PTB) 1 Ash, wt ppm 33 Vanadium, wt ppm 15 MicrocarbonResidue, wt % 3.84 Nickel, wt ppm 4 Nitrogen, wt ppm 542 Heating Value,Gross, BTU/Lb 19091 Kin Viscosity, @ 70° F., SUS 55.18 Kin Viscosity, @100° F., SUS 42.61 Debutanized Crude Gravity, °API 33.20Characterization Gravity, °API 28.60

In one embodiment, heavy crude oil and highly waxy crude oil havingproperties as outlined in Table 1 and Table 2, respectively, areprocessed by the method of the present invention. Heavy crude oil ismixed with highly waxy crude oil water in the ratio of 5:1 wt/wt at 158°F. (70° C.) with an impeller to form a modified heavy crude oil. Usingan impeller, the modified heavy crude oil is mixed with water in theratio of 1:5 wt/wt at 158° F. (70° C.) to form a modified heavy crudeoil/water mixture.

This modified heavy crude oil/water mixture is then fed, using a highpressure pump, into a heating zone to raise its temperature up to 482°F. (250° C.), forming a pre-heated mixture. The pre-heated mixture isthen introduced into a reaction zone while maintaining pressure at 25MPa and a target temperature of 842° F. (450° C.). The pre-heatedmixture has a residence time of 10 minutes within the reaction zone. Ahot adapted-mixture, which is the output from the reaction zone, is thenused to heat the modified heavy crude oil/water mixture via a heatexchanger before it is released to about 0.1 MPa by a back pressureregulator. Following this pressure release, the hot adapted mixture isthen fed into a liquid-gas separator, wherein the liquid portion fromliquid-gas separator is then fed into an oil-water separator. Theupgraded oil is then collected and analyzed. Total liquid yield is above95 vol %; the API gravity is 45, and the pour point of the upgraded oilis lower than 10° F. Conversion of asphaltene contained in residue above1050° F. was above 80% based on weight.

Now turning to FIG. 1, heavy crude oil [4] is combined with water feed[2] in the presence of highly waxy crude oil [6] in mixing zone [30] tocreate modified heavy crude oil/water mixture [34]. Mixing zone [30] canbe simply a “T” in the line allowing mixing or other mixing devicesknown in the art. Modified heavy crude oil/water mixture [34] is thenfed into main reactor [50] and subjected to increased temperatures andpressures, which preferably exceed the critical temperature and criticalpressure of water, which are about 705° F. (374° C.) and about 22.1 MPa,respectively. During this period of intense heat and pressure, modifiedheavy crude oil/water mixture [34] undergoes cracking and forms hotadapted-mixture [52], which is then sent to pressure regulating device[70]. Hot adapted-mixture [52] is brought back down to a pressure closeto atmospheric, resulting in pressure-reduced adapted mixture [72].Pressure-reduced adapted mixture [72], which contains both gases andliquids, is then fed into liquid-gas separator [80] to remove gasportion [82] from liquid portion [84]. Liquid portion [84] is then fedinto oil-water separator [90], which yields upgraded oil [92] andrecovered water [94]. Upgraded oil [92] is an upgraded version of bothheavy crude oil [4] and highly waxy crude oil [6], having reducedamounts of asphaltene, sulfur, nitrogen or metal containing substancesas compared to heavy crude oil [4]. Upgraded oil [92] also has improvedflow properties resulting from a lower pour point, which allows upgradedoil [92] to be transported to other processes using pipes or tankers.

FIG. 2 shows an alternate embodiment wherein at least a portion ofrecovered water [94] is used as a recycle stream and is combined withwater feed [2].

FIG. 3 demonstrates a further embodiment in which oily residue isremoved from recovered water [94], making treated water stream [112] viaoxidation reactor [110]. Treated water stream [112] is then combinedwith water feed [2].

FIG. 4 is another embodiment in which heavy crude oil [4] is combinedwith highly waxy crude oil [6] to form modified heavy crude oil [8].Modified heavy crude oil [8] is then heated, using modified heavy oilheater [65], which is preferably a heat exchanger, and then sent tomixing zone [30] where it is combined and mixed with water feed [2] toform modified heavy crude oil/water mixture [34]. Modified heavy crudeoil/water mixture [34] is then sent to heating zone [40], where it ispreferably heated to a temperature of about 482° F. (250° C.), beforebeing fed into main reactor [50]. The continuous process is then similarto that as shown in FIG. 3, with the additional step of passing treatedwater stream [112] through modified heavy oil heater [65] beforecombining with water feed [2]. The dashed line represents an alternatepath, wherein treated water stream [112 a] passes through heating zone[40] rather than modified heavy oil heater [65] in order to heatmodified heavy crude oil/water mixture [34] rather than modified heavycrude oil [8].

FIG. 5 shows an alternate embodiment in which the thermal energycontained in hot adapted mixture [52] is used for heat exchange upstreamof the liquid separation step. In one embodiment, the thermal energyfrom main reactor [50] is used for heating in heating zone [40] and thethermal energy released from oxidation reactor [110] is used to heatmodified heavy crude oil [8] via modified heavy oil heater [65]. Thedashed lines represent alternate paths, wherein treated water stream[112 a] passes through heating zone [40] rather than modified heavy oilheater [65], and hot adapted-mixture [52 a] passes through modifiedheavy oil heater [65] rather than heating zone [40].

FIG. 6 shows an alternate embodiment to that shown in FIG. 1, in whichthe thermal energy contained in hot adapted mixture [52] is used as theheat source for heating zone [40]. The dashed line represents analternate path, wherein the thermal energy is used as the heat sourcefor modified heavy oil heater [65] instead of heating zone [40].

FIG. 7 shows an alternate embodiment wherein high pressure pump [15] isused to feed modified heavy crude oil/water mixture [34] to heating zone[40] to form pre-heated mixture [42] before entering main reactor [50].In main reactor [50], pre-heated mixture [42] is subjected to increasedtemperatures and pressures, which preferably exceed the criticaltemperature and critical pressure of water, which are about 705° F.(374° C.) and about 22.1 MPa, respectively. During this period ofintense heat and pressure, pre-heated mixture [42] undergoes crackingand forms hot adapted-mixture [52]. Hot adapted-mixture [52] passesthrough heating zone [40] in order to transfer heat energy to modifiedheavy crude oil/water mixture [34]. Hot adapted-mixture [52] is thensent to pressure regulating device [70], where it is depressurized,preferably to 0.1 MPa, to form pressure-reduced adapted mixture [72].

FIG. 8 shows an alternate embodiment as that described in FIG. 7,wherein the thermal energy released from oxidation reactor [110] is usedfor heat exchange upstream of the liquid separation step. In oneembodiment, the thermal energy from main reactor [50] is used forheating heating zone [40] and the thermal energy released from oxidationreactor [110] is used to heat water feed [2], heavy crude oil [4], andhighly waxy oil [6] via modified heavy oil heater [65]. The dashed linesrepresent alternate paths, wherein treated water stream [112 a] passesthrough heating zone [40] rather than the modified heavy oil heater[65], the hot adapted-mixture [52 a] passes through modified heavy oilheater [65] rather than heating zone [40].

In FIG. 9, heavy crude oil [4] is combined with highly waxy crude oil[6] into crude oil mixer [5] to create modified heavy crude oil [8],wherein the mixing ratio of heavy crude oil [4] to highly waxy crude oil[6] is in the range of 50:1 wt/wt and 1:1 wt/wt, more preferably in therange of 20:1 wt/wt and 2:1 wt/wt. Additionally, the temperature ofcrude oil mixer [5] should preferably be in the range from 50° F. to392° F. (10° C. to 200° C.), more preferably in the range from 122° F.to 322° F. (50° C. to 150° C.).

Modified heavy crude oil [8] is combined with water feed [2] in mixingzone [30] to form modified heavy crude oil/water mixture [34], whereinthe weight ratio of modified heavy crude oil [8] to water feed [2] is inthe range of 10:1 wt/wt and 1:10 wt/wt, more preferably in the range of5:1 wt/wt and 1:5 wt/wt. Modified heavy crude oil/water mixture [34] isthen fed into main reactor [50], wherein modified heavy crude oil/watermixture [34] is subjected to increased temperatures and pressures, whichpreferably exceed the critical temperature and critical pressure ofwater, which are about 705° F. (374° C.) and about 22.1 MPa,respectively. During this period of intense heat and pressure, modifiedheavy crude oil/water mixture [34] undergoes cracking and forms hotadapted-mixture [52]. Hot adapted-mixture [52] is then separated intogas portion [82] and liquid portion [84] via liquid-gas separator [80].The liquid portion [84] then travels to oil-water separator [90],wherein liquid portion [84] is separated into upgraded oil [92] andrecovered water [94], whereby upgraded oil [92] is an upgraded heavycrude oil having reduced amounts of asphaltene, sulfur, nitrogen andmetal containing substances in comparison with the heavy crude oil.

FIG. 10 represents one embodiment in which water feed [2] is pre-heatedto supercritical conditions prior to mixing zone [30]. In thisembodiment, water feed [2] is fed into water storage tank [10], wherethe water feed [2] is subsequently pumped into the continuous processusing high pressure metering water pump [20]. However, instead of firstmixing with modified heavy crude oil [8], water feed [2], which is at apressure exceeding the critical pressure of water, undergoes heating inheating zone [40] to form heated water stream [41], wherein heated waterstream [41] is in a supercritical state.

Highly waxy crude oil [6] and heavy crude oil [4] are fed into crude oilmixer [5], which is preferably a stirred tank type mixer, and mixedtogether forming modified heavy crude oil [8]. Modified heavy crude oil[8] is slightly heated to allow for adequate flowing. Modified heavycrude oil [8] is similarly fed into modified heavy crude oil storagetank [11], where modified heavy crude oil [8] is subsequently pumpedinto the continuous process at mixing zone [30] using high pressuremetering modified heavy crude oil pump [21]. Mixing zone [30] can besimply a “T” in the line allowing mixing or other mixing devices knownin the art. Prior to mixing zone [30], modified heavy crude oil [8],which is at a pressure exceeding the critical pressure of water, is at atemperature that allows for flow; however, preferably not exceeding 150degrees C. Modified heavy crude oil [8] and heated water stream [41]combine at mixing zone [30], which is preferably near main reactor [50],to create pre-heated mixture [42].

Pre-heated mixture [42] enters main reactor [50], wherein thetemperature and pressure are near to or exceed the critical point ofwater, such that at least some of the hydrocarbons of pre-heated mixture[42] undergo cracking, forming hot adapted-mixture [52], main reactor[50] being essentially free of an externally-provided catalyst andessentially free of an externally-provided hydrogen source. Hotadapted-mixture [52] is then cooled using any acceptable means ofcooling [60], preferably a heat exchanger, creating cooledadapted-mixture [62]. Cooled adapted-mixture [62] is then depressurizedby pressure regulating device [70] to create pressure-reduced adaptedmixture [72]. In one embodiment, pressure regulating device [70]comprises at least two pressure regulating valves, and more preferablythree pressure regulating valves [70 a, 70 b, 70 c] connected in aparallel fashion. This arrangement advantageously provides for continuedoperation in the event the primary relief valve becomes plugged.Pressure-reduced adapted mixture [72] then enters liquid-gas separator[80], wherein pressure-reduced adapted mixture [72] is separated intogas portion [82] and liquid portion [84]. Liquid portion [84] is thenfed into oil-water separator [90] to yield upgraded oil [92] andrecovered water [94]. In an alternate embodiment, recovered water [94 a]can be recycled upstream high pressure metering water pump [20].

While FIGS. 4-6, and 10 show embodiments in which highly waxy crude oil[6] is combined with heavy crude oil [4] prior to the introduction ofwater feed [2], these are merely the preferred embodiments. As statedearlier, water feed [2] can be combined with heavy crude oil [4] beforeor after combining with highly waxy crude oil [6].

While the invention has been shown or described in only some of itsforms, it should be apparent to those skilled in the art that it is notso limited, but is susceptible to various changes without departing fromthe scope of the invention. For example, steps can be performed in adifferent order to reach the same desired goal and heating can beaffected in a variety of ways. Similarly, the process can be practicedas a batch or continuous-batch process without departing from the scopeof the invention.

We claim:
 1. An apparatus for upgrading heavy crude oil and highly waxycrude oil in an environment free of an externally supplied catalyst orexternally supplied hydrogen source, the apparatus comprising: a mixingzone operable to combine a heavy crude oil, which has an API gravity ofless than 30°, and a highly waxy crude oil, which has a having a pourpoint temperature greater than room temperature and has an API gravityof greater than 30°, with a water feed at a slightly elevatedtemperature to create a modified oil/water mixture; a pre-heating zonethat is fluidly connected with the mixing zone, the pre-heating zoneoperable to heat the modified oil/water mixture to a temperature up to350° C.; a high pressure pumping means, the high pressure pumping meansoperable to increase pressure of the modified oil/water mixture to atleast the critical pressure of water; a reaction zone comprising aninner portion of a main reactor, wherein the reaction zone is fluidlyconnected with the pre-heating zone; the main reactor being operable towithstand a temperature that is at least as high as the criticaltemperature of water; the main reactor being operable to withstandpressure in excess of the critical pressure of water, the reaction zonebeing essentially free of an externally-provided catalyst andessentially free of an externally-provided hydrogen source; a pressureregulating device; a liquid-gas separator fluidly connected to thepressure regulating device, the liquid-gas separator operable to createa liquid stream and a gas stream; and a water-oil separator fluidlyconnected to the liquid-gas separator via the liquid stream, thewater-oil separator operable to create a recovered water stream and anupgraded hydrocarbon stream.
 2. The apparatus of claim 1 where thepressure regulating device comprises a plurality of back pressureregulators connected in a parallel fashion.
 3. The apparatus of claim 1where the recovered water stream can be recycled and combined with thewater feed.
 4. The apparatus of claim 3 further comprising an oxidationreactor fluidly connected with the recovered water stream, the oxidationreactor operable to clean the recovered water stream via oxidation.